It is common to provide a single valve body to simultaneously supply the oil to a burner and vapor to atomize the oil. The vapor and the oil are controlled through their respective seats by separate movable valve elements within the cavity of the valve body. There are two basic positions of these valve elements. First, in the Run position, the oil valve element has been moved from its seat to enable the oil to flow through the cavity to the burner. At the same time, the vapor valve element has been moved from its seat to provide only the atomizing vapor outlet from the cavity as a route for the vapor. Alternatively, of course, both valve elements engage their respective seats to preclude passage of both oil and vapor through the cavity to the burner. A third position is provided for the elements which maintains the oil isolated from the burner while the vapor is flowed to both the oil outlet and the vapor outlet.
A valve construction representative of the arrangement described above is manufactured by Skotch, Inc., 278 Main Street, Portland, Conn. 06480. The valve is presently marketed under the trademark "Trifecta" and it has its valve elements, seats and vapor outlet positioned to provide less than a desirable amount of vapor to the oil outlet line during the purge position. There is need for a structure, at the vapor outlet from the body cavity, formed and arranged to provide a predetermined restriction to the flow of the vapor from the cavity through the atomizing vapor line. So restricted, the vapor within the cavity will be divided between the vapor outlet line and oil outlet line to adequately purge the oil outlet line to the burner.